On Wednesday, the prosecution case against Pistorius began to unravel with revelations of a series of police blunders and Botha's admission that authorities have no evidence challenging the double-amputee Olympian's claim he killed his girlfriend accidentally. Pistorius faces a charge of premeditated murder.

Meanwhile Botha, said to be an experienced police officer, came in for harsh criticism over his performance at Wednesday's bail hearing for the star athlete.

Called as a witness for the prosecution, he was expected to solidly nail points that would make it difficult for Pistorius, accused of fatally shooting his model girlfriend on Valentine's Day, to secure bail. Instead, his testimony cast doubt on the case against the star athlete.

Pistorius, 26, claims he shot 29-year-old Reeva Steenkamp after mistaking her for an intruder. He denies murdering her intentionally, as the prosecution aims to prove.

But Botha stumbled in his evidence, admitting investigators had walked over the crime scene without protective boots, and had overlooked a bullet that hit the toilet bowl - later discovered by the defence's forensic team.

Botha also appeared to discredit one of the police's own witnesses - who said they heard fighting in Pistorius's house on the night of the murder - by telling the court the house was 600 metres away. He later backtracked, saying it was in fact 300 metres away.

He also testified the substance found in a dresser in the athlete's bedroom was testosterone, which is banned by the International Olympic Committee.

But Pistorius's defence lawyer Barry Roux said the substance was in fact a legal herbal remedy.